Compassion
by Greensword101
Summary: AU. Change can happen in an instant. What started as a project to make a Healthcare robot ends up bringing more trouble than it's worth. And then there was his five-year-old brother to add to the variable...


**Author's Note:** Hello again. Just something I've been working on to get the mind flowing. To my _Dynamic_ fans, fret not, I am working on the next _real_ chapter as we speak. Some inspiration for this came from some deleted scenes from the film as well as uponagreydawn's fanart. A shame that they disappeared from fanfiction dot net and took down their art. At least people managed to create copies. Enjoy!

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 **Disclaimer: All Rights to Big Hero 6 Belong to Walt Disney Pictures and Marvel Comics**

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 **Chapter One: Boy Genius**

"This is Tadashi Hamada and this is the forty-fourth test of my robotics project."

 _Click!_

Moments later...

"Stopstopstopstopstop!" Tadashi struggled to get the flailing arms from hitting him.

 _Click!_

Tadashi sighed, massaging his cheek even though there was no bruising on it. He looked up at the calendar on the wall; first day of summer and he had to spend it cooped up at work and the garage. There was only a month and a half left before the due date and absolutely no way he was going to get this project done by the date of the showcase.

And worst of all, he was running out of money to fund his project. There was no way Aunt Cass was going to pool in her own money, something Tadashi would be horrified of if that happened. He needed to make progress on this somehow…

At least the power didn't go out this time like the previous test. Aunt Cass wasn't thrilled when that happened. Although, Hiro didn't mind reading the bedtime story with a flashlight. Tadashi grinned at the memory, recalling the spooky atmosphere he tried invoking on the five-year-old, even going as far as to cover himself in his own bedsheets while he recited the story he had in mind from memory.

Too bad the only person he scared was also the one tall enough to wield a broom without falling over. The result was Tadashi running around with the bedsheets over his head while Aunt Cass whacked at him endlessly, mistaking him for an intruder. After getting the bedsheets off himself, Aunt Cass gave him another lecture while Hiro broke down into giggles in the background.

It was nice to hear that sound. It told him that Hiro was fine.

"Dashi?"

The sound came from the door leading into the garage. Tadashi acted quickly, pulling a large cover over Baymax. He didn't want to spoil the surprise for his brother. Just as he finished hiding his project from unwanted eyes, Hiro walked in, the small kitten, Mochi, strolling right next to him.

"What is it, buddy?" Tadashi asked.

"I heard yelling. S'there a burglar?"

Tadashi shook his head. "Nope. But I'll tell you what did just happen." Hiro's eyes widened with excitement. Tadashi crouched down to eye-level and whispered into Hiro's ear.

"I was having an argument with a ghost."

Hiro gasped while Tadashi fought down giggles.

"We gotta call the police!"

That just made not laughing much harder. Hiro ran over to the nearest stool and dragged it over to the nearest phone.

"Quick, what's the number for the Ghostbusters?"

Tadashi gave in and let out a loud laugh, collapsing on the floor with tears streaming down his face. He could hear Hiro's frightened voice, his tiny hands shaking his broad shoulders. There was the sound of feet running for a few moments, before returning just as quickly. And then Tadashi felt something hit him in the back. Hard.

He looked up just in time to get one end of the broom in his face. And it was clearly the end that was meant for sweeping, Tadashi observed sarcastically as he spat dirt out of his mouth.

"Get out of my brother, you ghost!" Hiro looked determined with the large broom in his hand. He struggled to keep the large object straight as he brought it down on his older brother again. Tadashi grabbed it and pulled Hiro into his arms. Hiro began kicking at Tadashi's stomach before his older brother pinched his nose gently.

"Got your nose!" Tadashi teased.

"Dashi?" Hiro looked up nervously. He was probably wondering if Tadashi was fighting the "ghost" somehow. Deciding that he was dragging the joke too far, Tadashi began to ruffle Hito's hair gently, smiling when Hiro started to lean against his chest.

An idea formed in his head.

"Tadashi's not here anymore." Tadashi growled, gaging his brother's reaction. He almost smiled when he saw Hiro frowning; good, he wasn't scared. Mad, maybe, but not scared anymore. "Now there is only Zuul! And Zuul wants to give you a big hug and a TICKLE ATTACK!"

The room was quickly filled with giggles, Hiro desperately trying to free himself from his brother's grip. They must have been too loud, Tadashi thought later, when he found himself being attacked by a broom once more.

"Let go of my nephew or so hel- TADASHI! I'm so sorry, sweetie, I thought there was a burglar in here." Aunt Cass said, dropping the broom to the ground and began checking Tadashi for any injuries.

"That's what this knucklehead thought, too." Tadashi said with a chuckle, gesturing the small boy in his arms.

Hiro pouted. "That wasn't funny, Dashi! You scared me."

He looked towards Aunt Cass and continued. "Dashi started pretending he was being controlled by Zuul!"

"Zuul?" Aunt Cass raised an eyebrow.

Tadashi shrugged. "It was from that really old movie in the 80s with that funny actor."

"Bill Murry?"

Tadashi nodded.

"Okay." Aunt Cass said slowly. "Why were you pretending to be…Zuul?"

"Because I told Hiro I was talking to a ghost and when I started laughing, he thought I was possessed."

"Were you really talking to a ghost?"

"No."

"Then you're grounded for lying." Aunt Cass said flatly.

"What."

"Dashi's in trouble." Hiro said in a sing-song voice.

"Don't make me drop you." Tadashi said half-heartily. When he saw the look of fear in Hiro's eyes, he continued. "I'm not gonna drop you, buddy. Don't worry."

"Can you put me down?" Hiro asked.

"Alright." Tadashi said dramatically. "Go ahead and break your brother's heart by leaving him alone with the imaginary ghost that possessed me."

He placed a hand over his forehead at the end of this and shut his eyes for added effect.

"Stop it, Dashi." Judging by the sound of his brother's voice, Hiro was not amused.

Tadashi sighed and placed his little brother onto the ground. The moment his feet connected to the surface, Hiro dashed off, Mochi idly following the young boy behind.

Aunt Cass stayed where she was. She looked over to where Baymax was hidden and smiled.

"Am I really grounded?" Tadashi asked nervously. "Cause…there's something I need to get done soon and-"

"No, that was a joke." Aunt Cass smiled. Tadashi sighed in relief. "So why did you tell Hiro you were possessed?"

"I didn't. He heard me working in here and came running in. I told him that the noise was from a ghost, but he-"

Tadashi broke off to chuckle a little before continuing.

"You should have seen his face. He looked so serious, it was cute."

"And then what happened?"

"I cracked up, he panicked and took a page out of your book and started hitting me with a broom." Tadashi smiled ruefully.

Aunt Cass looked over his shoulder, still looking at the hidden project. "Are you ever going to let me see what you're working on?"

"Nope." Tadashi shook his head. "It's a surprise."

"And you have to get it done by the time the showcase starts?"

"I _want_ to get it done so I can show my professors what I'm capable of." Tadashi said insistently.

"Are you willing to pay the electric bill the next time you cause a power outage, then?"

Tadashi opened his mouth to reply and stopped. His face turned red when he realized the implications behind her words. His wallet was being drained by this, there was no way he could add paying the electric bill to his already high list of expenses.

He must have started looking down, because Aunt Cass gently placed her hand on his shoulder.

"Sweetie." She said. "I know how much this project means to you, but tackling it all the time isn't going to solve the problem. You need to take a step back sometimes and see what you're doing wrong."

"But this can help _so_ many people-"

"It can wait-"

"No, it can't!" Tadashi snapped. Aunt Cass's face faltered. Her eyes grew canny.

"It wasn't your fault, you know."

"Stop it." Tadashi walked past her. She shouldn't be talking to him about this again.

"It's been two years now-"

"I don't want to talk about it-" Why won't she leave him alone?

"Is this what your father would have wanted?"

"DAD'S GONE!" Tadashi shouted. He flinched at the sound of his own voice. "I'm sorry."

He felt his eyes grow hot, but no tears spilled over. This wasn't the reason he was working on Baymax; Baymax could help so many people. He just needed more time. Why won't Aunt Cass accept that? Why won't anyone accept that he's moving on-

Moments later, he felt himself being pulled into a warm embrace.

"I miss them too." Aunt Cass whispered.

He never wanted that to happen again. The phone call. Hiro at the tender age of three asking his older brother when Mommy and Daddy where coming home. The first weeks that followed, when he realized they weren't coming home. All of those sleepless nights. It wasn't fair. They could have been saved. They could have been-

No. Deep breaths. He needed to calm down. Hiro might be listening right now.

"Sorry." He muttered. "You're right. I need to take a break from this. I can work on it when the term starts."

"That's the spirit." Aunt Cass smiled. She looked down at her watch. "Yikes. It's getting kind of late, isn't it? The café needs to be open tomorrow and _you_ need to get some shut-eye. You can spend tomorrow morning sleeping if you'd like."

"That's nice of you to suggest that, Aunt Cass, but-"

"In fact, I expect you to be sleeping in tomorrow." Aunt Cass began to frog-march Tadashi out of the garage. "You have the day off, use it for something enjoyable."

Enjoyable, huh? Never thought that would be in the picture again…

"Dashi? What're you makin'?" Hiro stood on top of the chair, his torso barely making it above the table. Tadashi ignored the question and continued twirling the screwdriver in his hand clockwise. The robot he purchases several weeks back remained in its package until today. So many pieces to put together, and he still couldn't follow the manual properly. And from the looks at the debris before him, there was going to be more combinations to work with before pieces matched together. Normally, he'd prefer it if Hiro weren't so close to him while he was working. What if he got hurt? But this was the first-time Hiro could see him out of the garage, so the least Tadashi could do was let his brother watch him.

Thank goodness there wasn't any dread at seeing the boy put a small piece in his mouth like it was candy.

"Pass me the manual, Hiro." Tadashi said.

He felt the slick paper being thrust into his hand a moment later. Tadashi smiled at Hiro in thanks.

"Whacha makin', Dashi?" Hiro repeated.

"A robot." Tadashi said simply.

"Like the Iron Giant?"

"Nah. The remote-controlled kind." Tadashi said. He started frowning again. Why was it so hard for him to do this? He could have finished building it an hour ago. His eyes still felt heavy, there wasn't enough time in the world to enjoy his bed. His thoughts began to wander; to Mochi, to Baymax hitting him like an abusive spouse, to maniacal robots forming and collapsing like Lego pieces.

Tadashi felt his shirt being tugged at and turned to Hiro. Hiro looked confused. "How's that a robot?"

He placed the screwdriver down and faced Hiro more directly. "Most robots being used in the world can't think for themselves. They need someone to give them orders, like with your toy car."

"Why can't the robots do stuff themselves?" Hiro asked.

"Cause no one's really figured it out yet."

"But the movies, they, they, they had robots that could talk and walk and punch." Hiro threw his fist out as if that would emphasize his point.

Tadashi chuckled. This was really cute. "Sorry, buddy. That's not how robots really work."

"But the movies-"

"Are just movies, Hiro." Tadashi explained patiently. "Artificial intelligent is tricky, and I think those old movies are why we don't have robots that can think for themselves yet."

"Why?"

"Because they would want to take over the world." Tadashi said. He muttered the next part to himself, almost bitterly. "Either that, or people are afraid of progress."

"Can they fly?"

"No."

"Can they shoot lazers?"

"Nuh-uh."

"What _can_ they do, then?" Hiro stamped his foot, the chair he was standing on wobbled before Tadashi pulled Hiro into his arms, right as the chair fell.

"Pick things up, move them, not much." Tadashi replied. "But you know…"

He paused for a moment. _Should I really tell him about it?_

"What?" Hiro asked.

"There _are_ robots that can fight, but they're the size of the robot I'm making and are meant to fight each other." Tadashi said. "Bot-fighting's pretty popular around here. You know those channels with the monster trucks?"

"Yeah!" Hiro said excitedly.

"Well, that's kind of what Bot-fighting's like. Robots crushing each other."

"Cool." Hiro whispered.

"But." Tadashi held his hand up. He had to make this next part clear, or else he'd end up regretting this conversation for years to come. "It's against the law to bot-fight. So, if you try doing it, you'll get in a lot of trouble. And if that happens, you're going to have to deal with me _and_ Aunt Cass. Understand?"

Hiro nodded. Tadashi ruffled his hair and went back to examining the manual. Then he looked back at the robot, waiting to be assembled. It was a little difficult balancing his brother on his knee while he worked, but he was enjoying this.

His head started throbbing after a while from looking from the manual to the damn thing that refused to match the expected picture. Placing Hiro down on his chair, Tadashi walked downstairs with the manual in hand, desperate for some water and aspirin.

Mochi was nearly crushed by his large feet, the kitten baring its small mouth open to hiss. No audible noise came from its mouth. Tadashi muttered an apology to the creature, half-mindedly thinking that it was a weird thing to do.

But Aunt Cass did that frequently, even holding conversations with the kitten a few times, so it might have been her odd habit rubbing off on Tadashi. Just as long as she didn't start bringing in cats by the handful and licked them clean, he'd be okay with it.

The aspirin and water didn't seem to do much, but he had only just taken both several moments ago, all he could do now was wait. Maybe he should just take a break from robots in general for the rest of the day and start up a movie. Preferably something that wasn't noisy.

Speaking of noise…what was going on upstairs?

He could hear _beeps!_ and metal on wood, unless it was just his headache. When Tadashi made it upstairs, he saw Hiro kneeling on the table with the damned robot he was working on moving on its spider-like legs. Hiro looked in Tadashi's direction and waved. This took place in the course of five minutes…Tadashi was working on it for two hours and it took his five-year-old brother at least _ten_ _minutes_?! He didn't register the manual slipping from his grip. Nor the glass shattering on the floor.

"AUNT CASS, YOU GOTTA SEE THIS!"

"Is something on fire again?" Aunt Cass rushed in. Tadashi could only point at Hiro. Aunt Cass blinked. She said. "Hiro _did_ that?"

Tadashi could only nod.

"Aunt Cass, I helped Dashi! I helped him!" Hiro beamed, oblivious to the stares he was given. His smile faded a little when he noticed Tadashi standing still, like he was a statue. "Dashi?"

Tadashi didn't answer. He couldn't build a model by himself until he was ten. Da-someone always helped him before.

"Dashi?" Hiro sounded worried.

Two hours spent working on it with half success and Hiro finished it in ten minutes...

"Are you 'kay?" Hiro asked.

Tadashi felt his face grow warm. He made his way over towards Hiro, towering over the boy like he was a giant. And smiled. Without another thought, Tadashi wrapped his arms around his younger brother, feeling tiny hands squeezing his sides as best as he could.

"I am, Hiro. I'm...really happy." Tadashi finally answered.

"Cause I helped?"

"No." Tadashi responded. "You wanna know why?"

Hiro nodded.

He whispered into Hiro's ear. "Because my baby brother's a genius!"

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 **Author's Notes:** I actually started giggling when I began working on it. It felt good. There is already an idea in my mind on where this needs to go. Just let me know if there is anything I can do in regards to Tadashi's characterization that I could work on. Maybe how to make Hiro sound more like a five year old too. Thanks for reading!


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